This invention relates to an apparatus for transporting sheet-like recording carriers such as sheets of paper, envelopes or the like. Such a transporting apparatus may be, for example, an assembly of an automatic recorder, a printer, or the like. The recording carriers may be, for example, sheets of writing paper, cards, envelopes or the like.
The increased popularity and widespread use of conventional automated business machines incorporating high speed printers has significantly increased the productivity and efficiency of office workers. The increased speed with which business machines now operate provide operators of such machines with an opportunity to accomplish additional tasks.
The major problem associated with these conventional automated business machines is the occasional double feeding of sheet-like recording carriers, such as, for example, sheets of paper to be printed upon.
Ideally, the conventional machines automatically feed single sheets of paper such that when the printing is finished upon one such sheet, an identical blank sheet immediately follows and is thus quickly positioned for further printing. This continuous flow of paper sheets thus provides for the automatic feeding and positioning of single sheets without the necessity of these sheets being manually positioned, thereby reducing the overall time required to accomplish a given task.
However, the conventional automated business machines do not always feed the required single sheets of paper. Often, a plurality of sheets are fed into the machine causing blockage of the conveying path as the sheets move through the machine. Thus, the blockage resulting from the plurality of sheets causes the machine to malfunction. The improperly fed sheets must be manually removed from the conveying path prior to the machine being, once again, ready for proper operation.
In an attempt to remedy the problem of feeding a plurality of sheets, it has been proposed, for example, in German OS No. 27 11 173, to provide a baffle plate as a separating device having a separating flap provided with friction-increasing coating. The separating flap is pressed by a weak spring in the direction of feed rolls, without, however, touching them. The lead slot formed between the feed rolls and the friction-increasing coating on the separating flap must be adapted to the thickness of the particular recording carrier to be conveyed. Thus, adjustments must be made depending upon the particular recording carrier utilized thereby obviating some of the advantages gained in automating the recording carrier conveyance. Also, such an arrangement is relatively expensive, due to the separating flap provided with the friction-increasing coating.
Furthermore, it has been proposed to make the sheets pulled off the supply stack, jump over separating corners. However, such an arrangement is suitable only for paper up to a certain stiffness and is not suited, for example, for the use of cards or envelopes. This arrangement also risks the formation of "dog's ears" or bent corners on the paper due to the separating corners. "Dog's ears" or bent corners are unacceptable to users of these devices since paper in this condition has a slovenly appearance. Additionally, it has also been proposed to use passage stops as a separating device. However, these passage stops must be adjusted to the particular thickness of the recording carrier being utilized.
According to the present invention, a transporting apparatus for sheet-like recording carriers is provided which makes possible a continuous conveyance of single sheets of recording carriers and/or envelopes of variable thickness. The sheets are singularly separated from a supply stack and are conveyed to a platen without special adaptation of the apparatus to the particular thickness of recording carrier being used.
The apparatus according to the present invention provides for the conveyed sheets and/or envelopes to be held by the deflecting plane against a baffle plate. In this manner, a possibly prematurely conveyed sheet is detained at its advancing edge at the edge of the baffle plate until the preceding sheet is conveyed past the baffle plate. The sheet thus obtained may then jump the baffle plate with its front edge, whereby it is likewise deflected by the deflecting plane and is held in a similar manner against the baffle plate.
Sheets and envelopes to be printed upon may be stacked alternatingly by such a device in the supply stack and then fed continuously to the platen. In this manner, letters and their corresponding envelopes, for example, may be quickly and efficiently prepared and collated. By utilizing the present invention, a resetting for different thicknesses is not necessary. Similarly, it is also possible to convey sheets or cards of variable thicknesses in any sequence.
In a preferred embodiment of the present invention, the baffle plate may have a plane which, as compared to the vertical, is angularly slanted in the direction of the path of conveyance. As a result of the slanting position, it is easier for the sheet being detained to jump the baffle plate with its forward edge when a previously conveyed sheet vacates.
Since the baffle plate is to be disposed in the immediate vicinity of the stop surface, it is preferable that the baffle plate is attached to the element having the stop surface. More preferably, the baffle plate may be disposed in the middle of the conveying path in order to ensure a symmetrical load of the sheets to be conveyed during their separation.
The deflecting element may also be rearwardly extended in the direction of the supply stack and may be arched away from the supply stack. This embodiment thus provides an intake slot or gap between the surface of the deflecting element and the element having the stop surface. The intake gap, however, should be selected large enough so that even thick recording carriers are conveyed easily. This intake gap, therefore, serves for supporting the separating device, in which an upward by-pass of the sheets pulled off the supply stack, is prevented.